1. Field of the Invention
The present invention concerns ink containers for ink jet printers. More particularly, the present invention relates to a method for inserting an absorbent to be impregnated with liquid ink into an ink container, wherein the absorbent is larger than the receiving space of the ink container. The present invention also relates to an ink container receiving the absorbent inserted by the method.
2. Description of the Related Art
Hitherto, a printing device for a miniaturized ink-jet printing apparatus has been proposed in which an integral cartridge-type device includes a printing head and an ink container detachably mounted thereto. Such an integral cartridge-type device must apply a predetermined level of reduced pressure in the printing head with respect to the pressure in the ink container in order to obtain proper ink flow. One method for obtaining proper ink flow from the ink container to the printing head under such a reduced pressure is known in which the ink container receives an absorbent impregnated with ink.
In the process of manufacturing the above-described ink container, the absorbent is manually inserted into the ink container in a compressed state and then impregnated with ink. Such manual operation is time consuming and inadequate for high volume production. Also, the absorbent gets wrinkled when inserted and/or unevenly contacts the inner wall of the ink container.
As a result, the ink gathers in the wrinkles of the absorbent and/or in gaps between the absorbent and the inner wall of the ink container. The stagnant ink in the wrinkles and/or gaps remains unused, thereby preventing smooth ink flow and proper ink jetting for printing, thus deteriorating the print quality.
In order to overcome the above-described problem, a method is known in which the absorbent is evenly compressed by a jig before insertion into the ink container. This absorbent insertion method results in an evenly compressed absorbent that provides no room for ink to gather. However, the ink added to the absorbent still can not be efficiently supplied to the printer head.
In order to efficiently utilize the ink in the ink container, the density of the absorbent is preferably increased gradually toward the ink outlet to the printing head.
A method for producing a density distribution in an absorbent received in a container has been proposed in which the absorbent is inserted into the container through an opening where two pairs of opposing sides of the absorbent are evenly pressed by a pair of first pressing members and a pair of second pressing members respectively. The container is then moved to receive the absorbent while one of the remaining sides of the absorbent free from the first and second pairs of pressing members is pushed by a third pressing member. The first and the second pressing members are then removed in accordance with the timing of the third pressing member moving in.
Another method is also known for controlling the density distribution of the absorbent by the controlling the moving speed of the container and the friction coefficient between the absorbent and the pressing members.
In the above methods, however, the density distribution state in the absorbent is not readily stabilized. During repeated operation of the absorbent insertion process, the friction coefficient between the pressing members and the absorbent varies according to the amount of triboelectric charges produced by the friction between the absorbent and the pressing members and between the pressing members and the container and stored on the pressing members.
Moreover, these conventional methods do not sufficiently enable a desired density distribution in the absorbent to be obtained because the density distribution is intended to be produced by controlling only the timing of in-out movements of the pressing members.